This invention relates generally to railroads, and more specifically, to methods and systems for mapping railroad tracks.
At least some railroad tracks are mapped using known two-dimensional mapping technology that maps only the mainline track and establishes an offset distance for parallel tracks, and uses a single reference location for this mainline track. Specifically, two-dimensional mainline mapping enables a track to be mapped by determining the longitudinal and latitudinal coordinates of a plurality of points along a mainline track. Distances along this mainline track map are referenced to a single location for determining location of a train. The purpose for establishing offset distances to parallel tracks reduces the data storage and processing requirements for the system. The data points representing the track map are stored in a database and are used to form a linear map based on the distance defined between pairs of points. Accordingly, the linear map can be used to determine a distance traveled on the track. However, two-dimensional mainline mapping is limited to linear mapping, and as such is only capable of linearly mapping tracks that extend in a single direction (for example the x-direction), and is not capable of mapping tracks that extend in multiple directions (for example the x, y, and/or z-directions).
Using two-dimensional mainline mapping with a single reference point to map a complex structure may result in discrepancies when determining a distance traveled on the railroad. For example, a siding track may curve and extend in the x and y-directions relative to the mainline. Accordingly, to travel a distance “1000” in the x-direction, a train traveling on the track may have to travel a distance greater than “1000”. Further, a train may travel a distance greater than “1000” along a complex track, but never reach a distance “1000” in the x-direction. In another example, a train may start at a location “0”, travel through a loop a distance “1000”, and return to location “0”. Using a two-dimensional mapping system with a single reference point, the train would be assumed to have only traveled a distance “0” despite actually traveling a distance “1000”. Accordingly, the results obtained using two-dimensional mainline track mapping to map complex railroad tracks can be limited.